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A332535
Numbers that are not of the form p + 2^(2^k) + 2^q with p, q primes and k >= 0.
2
1, 2, 3, 4, 5, 6, 7, 16, 18, 20, 24, 28, 30, 32, 34, 40, 42, 44, 46, 48, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 136, 138
OFFSET
1,2
LINKS
Christian Elsholtz, Florian Luca, and Stefan Planitzer, Romanov type problems, The Ramanujan Journal 47.2 (2018): 267-289.
MAPLE
q:= proc(n) local k, i;
for k from 0 while 2^(2^k)<n do
for i while 2^(2^k)+2^ithprime(i)<n do
if isprime(n-2^(2^k)-2^ithprime(i)) then return false fi:
od
od; true
end:
select(q, [$1..200])[]; # Alois P. Heinz, Feb 15 2020
MATHEMATICA
q[n_] := Module[{k, i}, For[k = 0 , 2^(2^k) < n, k++, For[i = 1, 2^(2^k) + 2^Prime[i] < n, i++, If[PrimeQ[n - 2^(2^k) - 2^Prime[i]], Return[False]]] ]; True];
Select[Range[200], q] (* Jean-François Alcover, Nov 27 2020, after Alois P. Heinz *)
CROSSREFS
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Feb 15 2020
STATUS
approved